【摘要】：研究擋土墻上土壓力的問題一直備受人們的關(guān)注。目前,普遍用來計(jì)算土壓力的理論當(dāng)屬庫侖土壓力理論和朗肯土壓力理論,但是這兩種理論都是在一定的假設(shè)前提下使用的,應(yīng)用到工程實(shí)際中時(shí)計(jì)算的結(jié)果難免會(huì)產(chǎn)生誤差。首先庫侖理論認(rèn)為擋土墻在工作時(shí)為均勻平移的狀態(tài)是不合實(shí)際的,因?yàn)樵趯?shí)際施工過程中,擋土墻的位移模式可以有很多種;其二,該理論認(rèn)為墻后土體達(dá)到極限平衡狀態(tài)時(shí),利用在靜力平衡條件下列平衡方程,最終計(jì)算出土壓力大小也是不準(zhǔn)確的,因?yàn)樵诂F(xiàn)實(shí)情況下,土體并不能真正意義上達(dá)到極限狀態(tài),所以利用該方法計(jì)算出的土壓力往往比實(shí)際值小些;第三,庫侖理論的計(jì)算通常將墻后土體看作一個(gè)整體,那么也就忽略了實(shí)際情況下土體自身的應(yīng)力變化情況,計(jì)算的結(jié)果也不準(zhǔn)確。然而,朗肯理論雖然對庫侖理論做了改進(jìn),考慮了土體自身的應(yīng)力變化情況,但是卻忽略了擋土墻與填土接觸面之間的摩擦阻力,因而也是不準(zhǔn)確的。因此,為了加強(qiáng)現(xiàn)實(shí)情況下,擋土墻設(shè)計(jì)的合理性,需要切實(shí)的考慮影響擋土墻土壓力變化的各種因素。本文針對擋土墻位移模式以及位移大小的變化對主動(dòng)土壓力的影響,在諸多學(xué)者研究的基礎(chǔ)上,提出了一種改進(jìn)的計(jì)算理論。本文以剛性擋土墻為例,認(rèn)為其在實(shí)際施工中可能會(huì)發(fā)生三種位移模式:繞墻底轉(zhuǎn)動(dòng)(RB模式)、繞墻頂轉(zhuǎn)動(dòng)(RT模式)和平動(dòng)(T模式),并定義擋土墻從初始靜止?fàn)顟B(tài)移動(dòng)到極限主動(dòng)狀態(tài)時(shí)會(huì)存在一個(gè)“中間過渡狀態(tài)”,稱之為非極限主動(dòng)狀態(tài)。認(rèn)為擋土墻背離土體移動(dòng)的過程中,隨著墻體位移的增大,填土摩擦角也逐漸發(fā)揮出來,引入摩擦角發(fā)揮值的概念,建立摩擦角與位移之間的關(guān)系;同時(shí)墻背所受主動(dòng)土壓力值也因?yàn)槲灰频脑黾佣鴱撵o止土壓力狀態(tài)逐漸減小,慢慢趨向于極限主動(dòng)土壓力值,此時(shí)就可利用摩擦角與位移之間的關(guān)系,求解出土體處在非極限主動(dòng)狀態(tài)下的主動(dòng)土壓力值。最終可以得到剛性擋土墻在不同位移模式、不同位移大小時(shí),其在非極限狀態(tài)下的主動(dòng)土壓力大小、分布以及合力作用點(diǎn)的位置等情況,并把本文方法求得的結(jié)果與已有計(jì)算理論及試驗(yàn)論證結(jié)果進(jìn)行對比,得出利用本文方法來計(jì)算出的主動(dòng)土壓力值更精確,在擋土墻的設(shè)計(jì)使用中將更合理、更科學(xué)。
[Abstract]:The study of earth pressure on retaining wall has been paid more and more attention. At present, Coulomb earth pressure theory and Rankine earth pressure theory are commonly used to calculate earth pressure. However, these two theories are both used under certain assumptions, and the calculation results will inevitably produce errors when applied to engineering practice. First of all, Coulomb theory holds that the state of uniform translation of retaining wall is not practical, because in the actual construction process, there can be many kinds of displacement modes of retaining wall. Second, the theory holds that when the soil behind the wall reaches the ultimate equilibrium state, it is also inaccurate to calculate the earth pressure finally by using the following equilibrium equations under the static equilibrium condition, because in reality, The soil can not reach the limit state in real sense, so the earth pressure calculated by this method is usually smaller than the actual value. Thirdly, the Coulomb theory usually regards the soil behind the wall as a whole, so the stress variation of the soil itself is ignored, and the calculation results are not accurate. However, although Rankine's theory improves Coulomb's theory and takes into account the stress variation of the soil itself, it ignores the friction resistance between the retaining wall and the filling interface, so it is also inaccurate. Therefore, in order to strengthen the rationality of the design of retaining wall, it is necessary to consider the factors that affect the change of earth pressure. In view of the influence of displacement mode and displacement on active earth pressure of retaining wall, an improved calculation theory is put forward on the basis of many scholars' research. Taking rigid retaining wall as an example, it is considered that three kinds of displacement modes may occur in actual construction: rotation around the bottom of the wall (RB mode), rotation around the top of the wall (RT mode) and peaceful movement (T mode). It is also defined that there will be a "intermediate transition state" when retaining wall moves from the initial static state to the ultimate active state, which is called the non-limit active state. It is considered that with the increase of wall displacement, the friction angle of fill soil is gradually developed in the process of moving away from the soil. The concept of exertion value of friction angle is introduced, and the relationship between friction angle and displacement is established. At the same time, the active earth pressure on the back of the wall decreases gradually from the static earth pressure to the limit active earth pressure because of the increase of displacement, and the relationship between friction angle and displacement can be utilized. The value of active earth pressure in non-limit active state of soil is calculated. Finally, the active earth pressure, the distribution of active earth pressure and the position of working point of the rigid retaining wall in non-limit state can be obtained under different displacement modes and different displacements. The results obtained by this method are compared with the existing calculation theory and experimental results. It is concluded that the active earth pressure calculated by this method is more accurate and more reasonable and scientific in the design and use of retaining wall.
【學(xué)位授予單位】：安徽建筑大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU476.4;TU432

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相關(guān)期刊論文 前1條

1 岳祖潤,彭胤宗,張師德;壓實(shí)粘性填土擋土墻土壓力離心模型試驗(yàn)[J];巖土工程學(xué)報(bào);1992年06期

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本文編號：2358223